Measuring instrument



Aug. 7, 1228. l 1,619,524

' C. G. HERSHEY MEASURING INSTRUMENT original Filed March 4, 1924 2-sheets-sheet' a 60-z l l 32 ATroRNEY Patented Aug. 7, 192.8.

UNITEDSTATE Parent ortie E.

carin GOEHM HEfEsrrEY', 0E YEr. raso, `Trixies,AAssrerioiiroIlili/iiigardaity stint/rind AND EEEmrNG COMPANY, 0E NEW YORK, n. Y.; Aconronnrron 0E nEW JEESEY.

MEASnEiNG INSTRUMENT.

originar' application fir-ea' March 4, 1924,- sena-i No; 696,823.'Divided and this application inea-April 4,

1925; serial No. 20,626.4v

This invention relates to instruments for measuring, indicating andrecording electric' differencesof potential.` i

The invention is especiallyinten-ded forV use in measuring relativelyhigh electric dif# ferences of potential, and provides a. device whichis vcaztremely light and simple in conf struction and sensitive inoperation The moving parts are light and are conveniently mounted so asto' reduce frictiona-ll contacte Movement of the parts is dampened bythe utilization of `lio[`uid of suitable densityy the samelidtrid'preferably formingpartofA the insulating medium and animportantl feature of the invention is that the insulat ing mediuni.'comprises both aV so'lid anda liquid material: ThusA one of theyelectrodes may be positionedout of contact Withthe liquid materiahandin' position Wherefit can beeasily inspected;

Various other objects'y and advantages lof theinvention 'Will be' inpartobvious from an inspection of `the accompanying dra-Wings and inpart will be more fully set forth in 7 the following particulardescription of one form of mechanism embodyingv my inven# tion, andtheinvention alsol consists in certainnewv and novel features ofconstruction and combinationfof parts hereinafter set forth and claimed.p

` This application is a division of my application for improvements inmeasuring instruments, Serial No. 696,823, filed March 4, 1924. i

` In the accompanying drawings:

Figure lsliowsa sectional elevation of an instrumentA embodying featuresof the inveu#v tion;

Figure 2 is a sectiontaken on the line2-2 of Figure 1;

Figure 3 is a section taken onthe 11ne33 off Figure 2; and

Figure t 1s a section taken on the line 4-4 n of Figure 3.d i

V'Referring' to the' drawings',,V there is a casi of mouldedmicaortli'el like, having' a' separable back cover 11, a front shelf 12 anda top 13. A portion of the front of the casing 10 above the shelfr12- istransparent, being formed of a glass window 14; This permits ofconvenient observation and 1nspectionV of the actuatinglinechanism"Within 'the casing; The back cover plateis hinged alongfoney edge, as at15, by "means of a.

suitable hinge. Adjustably secured'to the lower face of the shelf 12 bymeans of a pair.`

of. adjusting screws 16, lis a bracket 17. Pivotally mounted on a hinge18 is an insulating instrument board 19, formed of i moulded mica or thelike.

For recording the' measurementsV to be made, there; is providedarecording,mechanism, includ-mtg` a clock 20 mounted upon the rear upperface of the board 19. The clock 20 has a main vshaft 21 driven by theclock mechanism Y at a constant rate of speed. Mounted upon the shaft'21 to rotate there-` with is a metal chart holder 23. The chart holderis preferablysubstantially `flat and smooth,` forming,` a mountinglforarecording` chart 24. The chart 24 is replaceable and its surface issuitably prepared. i 1 .f

The chart may have printedthereon cir-V i cular concentric divisionlines, such 25, 25, the spacing of which is calibrated to desired unitsof measurements, such as onc'hundred volts. The chart may also bedivided by division lines, `such as2G,26, transverse to the concentriclines, the spacing being calibrated to umts of time, such as quarterhour periods.l It will be seen that the clock is made accessible byrotating the Yback cover 11 about itshingge 15 in a clockwise directionas seen in Figure 2, and thatthe chart holder Vis made readilyaccessible by simi-lar-` ly rotatingthe instrument board19 in a similardirection about its hinge 18," i

The indicating mechanism includes a stationary electrode plateadjustably mounts ed upon `itl-plurality of threaded studs such as' 31each clamped at its lowerend to the bottom ofthe casing1'0- Mounted uponthe electrode plate 30 'is a vat or container 32,

preferably formed of glass, and there is pro vided Within-the containeri32, a suitable quantity o'fA oil or other substance-33, for dampeningthe'movement' of the moving parts, as Will hereinafter appear'.` The plate30 is formed of metal,-

is a conductor of electricity, and is connected by means of a conductingstrip 34 fastened toone stud 31 `(see Figure 1)I to a binding post 35and by Way of a conductor 36 to one pole of a source of electricpotential difference, (notsho'Wn) the voltage of Which is to bemeasured; The container 32 is held securely in place by suitable angles,such as 37 37, fastenedV to the interior ofthe casing 10.

Secured to the bracket 17, as by being bolted thereto, is a ring 40,forming a mechanism support. There is mounted upon this ring, insubstantially horizontal alignment and diametrically opposed, a pair ofelongated bolts 4l, 4l, and upon the outer ends of these bolts aremounted a pair of spaced bars 42, 43, (see Figure 3). Suitable sleeves44, 44 are provided upon the bolts 4l as shown, so that the bars 42 and43 are held in substantially,parallel and spaced relation to the planeof the ring 40.

For reducing the friction of the moving parts of the mechanism to aminimum, there yis provided a pair of jewel bearings 50 and 51 aliixedupon intermediate portions of the bars 42 and 43, respectively andopposite to one anotheiz These form a support forV a rotatable trunnion52 upon which there is mounted for rotation therewith a radial pointerarm 53, an operating arm 54 and a counterweight arm 55. The operatingarm has a saddle .in whichis pivotally mounted a link 56 extendingdownwardly therefrom.

For actuating the indicating mechanismY connects electrically thetrunnion 52 and a bracket 64 fastened to the bar 42 without materiallyinterfering with the rotary movement of the trunnion 52.

The electrode 60, cradle 61, lead 62, link 56, trunnion 52, hairspring64, bars 42 and 43,and ring 40 are formed of electrically conductingmaterial. A conductor 65 connects the ring40 with a binding post 66positioned in the upper portion of the casing lO. A conductor 67 extendsfrom the binding post 66 to the pole of the source of electric potentialdifference the voltage of which 4is to be measured oppositel to the poleconnected to the conductor 36 hereinbefore ment-ioned.

The casing lO is provided with a. plurality of'hollow legs such as 70,each of which is internally screw threaded for the reception rof aninverted bolt, the head 72 of which rests upon the floor 73. To takecare of any irregularities of the floor the several bolts 7l are adjustably positioned so that the fixed electrode 30 is substantiallylevel, and thus inv substantial parallelism with the suspended electrode60.

Then used as an electrostatic voltmeter the device may be calibrated'byapplying a known voltage across the binding posts 35, 66. Thesuspended'electrode 60 is attracted towards the fixed electrode 30, inaccordance Vthus friction is reduced to a minimum.` fr

record is made of the successive indications by passing a spark betweenthe pointer arm and the chart, the latter having been prepared for thatpurpose. This chart is acted upon by the action of the spark and whenacted upon forms a record. f

Thus it will be seen that I have provided an improved indicating andrecording instrument for high electric voltage, in which a legiblerecord is made without unnecessary contact and friction between theindieating mechanism and the recording mechanism. The records are madeupon calibrated charts which may be readily replacedwithout disturbingthe indicating mechanism. Access may be had to the clock mechanism foradjustment thereof without disturbing the calibration of the indicatingmechanism.

Positive reliable electric contact is made to the moving parts of theindicating mechanism, by means of simple and rugged conducting means.Levelling and other adjustments of the mechanism may be effected in apositive manner.

The partsof my improved measuring device are simple, cheap and easy toassemble, and the structure is particularly well adapted for the purposefor whichit is intended.

While IY have shown and described and have pointed out in the annexedclaims certain novel features of my invention, it will be understoodthat various omissions, substitutions and changes in the form anddetails of tbc device illustrated and in its operation may be made bythose skilled in the art without departing `from the spirit of myinvention.

Having thus described my invention I claim; 1. In a measuringinstrument, the combination of a stationary electrode and a movableelectrode, means for conducting to said electrodes opposite charges ofelectricity respectively, and means separatingV said electrodescomprising a solid and a liquid insulating material,

2. In a measuring instrument, the combination of a vat formed of amaterial which is a non-conductor of electricity, a mass` of liquidmaterial which is a non-conductor of electricity, and a pair ofoppositely charged, relatively movable electrodes, one within and loneoutside of said vat.

l UU

3. In a measuring instrument, the combination of a stationary electrodeand a movable electrode arranged to be charged ,electrically atditfcrent electric potentials respectively, and means formed of aninsulating material for maintaining a mass of nonconducting liquidaround said movable eleceonducting liquid around said movable electredefor damping the movement of the electrode, said maintaining means andsaid damping liquid forming insulation between the electrodes.

5. In a measuring instrument, the combination of a vat for containing anonsconducting liquid, a stationary electrode outside of said vat, and amovable electrode submerged in said liquid and maintained at a potentialdifferent from that of the stationary electrode.

G. An electrostatic voltmeter, including attracting and attracted parts,and means for separating said parts comprising a solid and a liquidinsulating material, one of said parts being submerged in the liquidinsulating material.

7. An, electrostatic voltmeter, including attracting and attractedelectrodes, means for separating said electrodes comprising a solidinsulating material and a liquid insulating material, one of saidelectrodes being submerged in the liquid insulating material, and meansfor supporting the submerged electrode and for conducting an elect-riccharge thereto. Y Y p 8. In a measuringinstrument, the combination of astationary electrode and a mov`- able electrode arranged to be charge-delectrically vat dierent electrical potentials respectively, means forseparating said electrodes comprising a solid insulator and a liquidinsulator', the solid insulator being arranged to maintain the liquidinsulator in predetermined position with respect to the movableelectrode to dampen the movement thereof.

9. In a measuring instrument, the combination of a stationary electrodeand a movable electrode arranged to be charged electrically at oppositeelectrical potentials, and means for maintaining a mass ofnon-conducting liquid between said electrodes forl dampening themovement of the movable electrode and for electrically insulating theelectrodes from each other, said means including a solid insulator forinsulating the electrodes.

10.' In ammeasuring instrument, the combination of a vat for containinga non-conducting liquid, a fixed electrode outside of the vat, anda'movable electrode submerged in said liquid, said vat being formed of anonconducting material.

ll. In a measuring instrument, a vat of dielectric material containing aliquid dielectric, a stationary electrode outside said vat, a movableelectrode immersed in said ,Y

liquid, an indicator shaft pivoted above said vat and having anoperating arm, a suspension element for suspending saidA movableelectrode from said arm. Y

l2. In a measuring instrument, a vat of dielectric material containing aliquid dielectric, a stationary electrode .outside and on the bottom ofsaid vat, a movable electrode immersed in said liquid above said so Ystationary electrode, an indicator shaft pivoted above said movableelectrode and hav-V ing an operating arm, a suspension element Y forsuspending'said movable electrode from said arm, said shaft having acounter-weight and pointer. v i

In testimony whereof I have hereunto set my hand.

Y CARL GORI-IAM HERSlI-IEY.

